The present invention relates to an ultrasonic measuring device for determining bone density and structure.
Electronic devices for examining bone tissue and structure are known, which comprise an ultrasonic transducer for feeding pulses into a bone segment for examination (e.g. a finger); a receiver for picking up the pulses that have traveled through the bone segment; and processing circuits for representing the waveform and, given the distance between the transducer and the receiver, calculating the speed of the ultrasonic signal through the bone segment. As the transmission speed of the ultrasonic signal is greatly affected by the characteristics of the bone segment between the transducer and the receiver, and varies alongside a variation in bone structure and density, known devices compare the measured speed value with a reference value to determine a variation in bone structure and density, which normally indicates demineralization of the bone tissue (caused, for example, by osteoporosis). The waveform is also examined by a skilled technician to obtain information, albeit approximate and at times ambiguous, concerning the characteristics of the bone segment. As such, known devices fail to provide for precise analysis closely related to the characteristics of the bone tissue, and interpretation is further complicated in the event the bone segment comprises a distal portion. That is, the distal portion of a bone (FIG. 8) is known to comprise a substantially solid first end portion A (metaphysis) defined by a shell of thin cortical bone containing mainly bone trabeculae; and a more proximal, substantially tubular second portion B (diaphysis) comprising an outer tubular (cortical) portion defining an inner canal containing few bone trabeculae, which, in adults, are reabsorbed to hollow out the canal of the second portion.
A known device measuring the above distal portion produces a waveform and calculates the ultrasonic speed of an ultrasonic signal traveling indifferently through the first and second portions, which, as stated, have entirely different structures. As certain bone diseases, however, have a widely differing effect on the first and second portions, a separate analysis of the structural characteristics of the first (metaphysis) and second (diaphysis) portions would be extremely beneficial.
It is an object of the present invention to provide an ultrasonic measuring device for determining bone density and structure, designed to overcome the drawbacks of known devices by, among other things, discriminating between the characteristics of the first and second portion.
According to the present invention, there is provided an ultrasonic measuring device for determining bone density and structure, as claimed in claim 1.
The present invention also relates to a method of determining bone density and structure, as claimed in claim 12.